Theory and Simulation of Laser-dressed Molecules and Materials

Ignacio Franco of the University of Rochester is supported by an award from the Chemical Theory, Models and Computational Methods program in the Division of Chemistry to develop the theory and simulation of the emergent properties of matter when driven or “dressed” by lasers. Characterizing and controlling matter driven far from equilibrium by lasers represents a key challenge for science and technology.

This is because matter can behave very differently when shaken by the intense coherent light provided by lasers. Further, lasers offer the possibility of manipulation on an ultrafast timescale (on the order of a millionth of one billionth of a second), something that is simply not achievable by more conventional means such as an applied voltage, chemical or thermodynamic control.

The Franco group will develop general schemes for the laser control of electrons in matter and, in doing so, catalyze the development of a novel class of laser-dressed dynamical materials with effective properties that are tunable “on-demand" on ultrafast time scales. For example, the group has pioneered schemes to use of light to drive ultrafast electronic currents and construct ultrafast logic gates that now enable information processing at the fastest time scales allowed by nature.

In addition to its interest at a fundamental level, manipulating electron dynamics with lasers is the basis for the development of ultrafast electronics, switching, imaging, catalysis, and, in fact, any science and technology at large based on electrons and their control. The outreach activities of this proposal include the organization of annual conferences exploring quantum frontiers in molecular science, integrating research with education by developing a graduate course on “Quantum Dynamics”, and advancing initiatives to increase diversity in STEM at the University of Rochester.

Specifically, the Franco group will investigate the fundamental limits in the quantum control of electrons and advance our capabilities to use intense ultrafast laser pulses to manipulate electronic properties and dynamics in nanostructures and extended systems. The general objective is to understand the ability of laser-dressed matter to absorb light, transport charge, and the use of light to control electron dynamics.

For this the group will develop: (a) A Floquet theory and simulation scheme of the optical absorption properties of realistic laser-dressed solids as needed to make experimentally testable predictions and stimulate experimental progress. (b) The theory and simulation of the emergent field of petahertz electronics where strong few-cycle laser pulses are used to trigger femtosecond currents along nanoscale junctions. In particular, we aim at clarifying the role of the electrodynamic propagation of light in this complex electromagnetic environment in the current generation. (c) A practical scheme to capture radiation-matter interactions beyond the dipole approximation while avoiding cumbersome multipolar expansions.

We will use it to quantify the influence of the spatial structure of light in nanojunctions in (b). The project will train 2 Ph.D. students in state-of-the-art methods in quantum dynamics and light-matter interactions. All codes developed as part of this project will be made available for general use through GitHub, impacting the ability of the broader scientific community to model strong light-matter interactions.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.